Design of Restart button doesn't match other buttons

[Nancy-Salpepi]

For phetsims/qa#838
The restart button has a light gray outline around each component that isn't present in the other buttons. This inconsistency is also in the published version.

[arouinfar]

Thanks @Nancy-Salpepi.

@samreid can you remove the stroke around the icon on the restart button? If not, let's at least make the stroke black so the icon looks more consistent with the other buttons.

[samreid]

This common code component is also used in Wave on a String, Collision Lab and My Solar System. Should it be changed for all occurrences? If not, what should the default be?

[arouinfar]

@samreid the stroke appearance should match the icons on the PlayPauseButton and StepForwardButton. The change can apply universally to all sims.

[zepumph]

@samreid and I reworked the design, removing the grey stroke and updating the icon to look more like the other play/pause icons.

My solar system:

Gravity and orbits:

We also glanced at https://fontawesome.com/icons/backward-fast?s=solid&f=sharp for inspiration.

Anything else here @arouinfar?

[arouinfar]

Looks great, thanks @zepumph @samreid.

[Nancy-Salpepi]

Looks perfect in master and in 1.6.0-rc.3. Closing!